What is Stormwater?

Stormwater runoff is water from rain or melting snow that ‘runs off’ roads, parking lots, sidewalks, lawns and paved areas. This runoff usually flows, untreated, into the nearest storm drains, which lead to the water bodies we use for drinking water, swimming and fishing.

Why is it important?

Stormwater can pick up debris, chemicals, dirt, fertilizers, pet waste and other pollutants and flow into a storm drain or directly to a lake, stream, river or wetland. Polluted runoff can have many negative impacts on plants, fish, animals and people, including contaminating drinking water supplies. Debris washed into water bodies can choke, suffocate, or disable aquatic life like ducks, fish and birds. It also ruins the beauty of our ponds and lakes. Sediment particles cloud water and smother habitats for fish and plants. Nutrients like phosphates and nitrates can promote excessive algae growth, which removes oxygen from the water. Toxic substances such as antifreeze and oil from leaking cars, as well as carelessly applied pesticides, can threaten the health of fish and other aquatic life. Land animals and people can become sick from eating diseased fish and shellfish or ingesting polluted water. Bacteria, viruses and parasites from pet waste can create health hazards, often making nearby lakes, rivers and beaches unsuitable for wading, swimming or fishing.

Your watershed and water bodies

In the Northern Middlesex region, our main watershed includes the Merrimack River and its tributaries - the Concord River, Nashua River, Stony Brook and Beaver Brook.

The Northern Middlesex region’s watershed and water bodies play an important role in the quality of life we enjoy. They provide us with recreation and drinking water, support tourism, and are used by industry. The Merrimack River is a source of water for drinking supplies, swimming, boating and bathing. If you live in Lowell or Tewksbury, your drinking water comes from the Merrimack River. These waters, however, are vulnerable to pollution from a wide variety of sources.

Many of the region’s water pollution problems are due, in large part, to pollutants that “run off’ roads, parking lots, sidewalks, lawns and paved areas during storms. Many people think that stormwater is "clean" and does not harm the environment. While this opinion is understandable, as the amount of pollution from any one place is not usually significant, when all of these small contributions are combined, they can cause water quality problems.

How is Stormwater Regulated?

The federal Clean Water Act establishes standards for surface water and makes it unlawful to discharge pollutants into the Waters of the United States, unless permitted. In 1987, Congress changed the Clean Water Act by declaring the discharge of stormwater from certain industries and municipalities to be a point source of pollution. Due to this change, certain stormwater discharges now require a National Pollutant Discharge Elimination System (NPDES) permit or water quality discharge permit. In Massachusetts, the NPDES is administered by the United States Environmental Protection Agency (EPA).
The Clean Water Act requires large and medium sized cities and towns across the United States to take steps to reduce polluted stormwater runoff, including the following:

Conduct outreach and education about polluted stormwater runoff.

Provide opportunities for residents to participate and be involved in conversations and activities related to reducing polluted stormwater runoff.

Detect illicit discharges (e.g. straight piping or dumping).

Control construction site runoff.

Control post-construction runoff.

Perform municipal housekeeping (e.g. take steps to prevent runoff from city buildings and activities.